Accrued Expenses and Other Current Liabilities (Detail) (USD $) In Thousands	Jun. 30, 2011		Sep. 30, 2010
Schedule of Accrued Liabilities [Line Items]
Compensation	$ 76,251		$ 56,047
Sales and marketing incentives	17,174	[1]	40,780	[1]
Professional fees	13,187		9,908
Accrued business combination costs	10,038		10,197
Sales and other taxes payable	9,091		5,211
Cost of revenue related liabilities	9,325		10,028
Acquisition costs and liabilities	8,299		4,970
Income taxes payable	2,960		4,357
Security price guarantee			1,034
Other	11,307		9,089
Total	$ 157,632		$ 151,621

[1] The decrease in accrued sales and marketing incentives was driven by an €18.0 million ($23.4 million equivalent) payment in December 2010 for a fixed obligation assumed in connection with our acquisition of SpinVox. The related €18.0 million of restricted cash was placed in an irrevocable standby letter of credit account at the end of fiscal year 2010 and was released upon satisfaction of the liability in December 2010. At June 30, 2011, we have an additional €5.0 million ($7.2 million equivalent) of restricted cash that has been placed in an irrevocable standby letter of credit for a related liability.